The 360 could be $100 and probably still wouldn't outsell the Wii.
As other people have said, most people want the Wii just for Wii Sports and Wii Fit.
Microsoft could steal probably some of the Wii audience but a majority of them are people who only buy a few of the games and were once non-gamers. If anything Microsoft is mainly out there to get people to buy a 360 over a PS3, so they'll focus on getting more of the PS3 owners or non PS3 owners to buy a 360.
It's just that simple.







